Underreamer



`April 2, 1946- w. B. DUNLAP, JR 4 2,397,652

UNDERREAMER Filed Feb. 5, ,1944 5 sheets-sheet 1 APM 2,l i946. W. E. DUNLAF, .JR 2,397,652

I UNDERREAMER Filed Feb. 3, 1944 3 Sheets-Sheel 2 April 2, 1946- w. BqDUNLAP, .JR 2,397,652'

UNDERREAMER Filed Feb. 3, 1944 3 Sheets-Sheet 3 Patented Apr. 2, 1946 #rmnnannmca 'Weyman'BJInlap, ngflloustonfmex. iimi1ianimare'.:mans `s, raigtsemmoaszasss reclaim. (onzas-ate) {Ehis ,invention -relates tto underreamen 'An :object :of -the y:invention is =,to lprovide lunderreamen specially. designed forrunderreaming. .or-,enlarging the, lower endsi` .ofy holes, on bpresafcr .treceiving foundation piers,v .pi1ing-.and ,the-,like

l,It ,is anotherobject of E,thefinvention .togirovide an.tunderreamenshaped-.to:beeadily loweredinto .a. hole.or bore previously .formed'. and havingsoutwardly movable yblades, for cutters, whereby .-.tlie lower end of I.the .bore l:may begradually :enlarged Eto tthe `.desired extent, :said :blades fbeing t retract- Aableftmpermit.thereadyWithdrawal:ofatheaumien# reamer fromthe bore,-.on-.hole. Theunderreamed bore may then be filled with Aillastic,fcnncretious Tmaterial which, .wh-enfset, willrhavefarelatively .'largeisupporting base.

The rinvention .also vemboiiies 4:novl imeans :for nexpanding, 01 retractingzthe .reaming fbladea; .or cutters.

:Another :object of 'the invention :is :to zprovide -an.underreamerfhavingafsubstantiallyizcylindrical jnnntainer, for ibucket, ihaving a llower fend spiate :zandhavin'g sideslotsthrougn` Whichithesreaming .:blades-:work, :said :blades being 7"shaped L'to-@gradu -ally move the lcuttings inwardly, -:as fthe -aunderk :reamer is rotated, to collect the l'cuttingslvlithin fthe :container for -bucket, andaupcn retraction 'ef vthe vreaming blades lto 'close said sli'deeslotsfand retain the cuttings within the -eontainer upon withdrawalfof-the underreamer. The invention also embodies novel means for centering the underreamer in the bore during the rotation or operation thereof as well as means for collecting, 'into the bucket, the loose earth that may be at the bottom of the bore.

lThe invention also embodies novel guide means for accurately guiding the reaming blades.

It is a further object of the invention to provide means for holding the retainer rmly against the bottom of the bore while the reaming blades are being retracted.

With the above and other objects in view -th invention has particular relation to certain novel features of construction, operation and arrangement of parts, an example of which is given in this specication and illustrated in the accompanying drawings, wherein:

Figure 1 shows a side elevation of the underreamer, partly in section, showing the reamer blades retracted.

Figure 2 shows a side elevational view', partly in section, taken at right angles to the view shown in Figure 1.

Figure 3 shows a vertical, sectional view show- 'fthe treaming sblades zin expanded, or factive, mcsition.

TFigure 14 esl-rows ea atqp plan sview =showing :the reamnigbladesimactivaposition.

Eigene showsfa cressasectionalwiew ztakenf on athelineSS-- ntFigm-e l.

fligure'eshowsea lamer-end View, and

Figure .f7 hovvs va sfragmentany, Nautical, `:secftionalfviewrof theabucket. l c :Referring @now-amore naarticularlyltoathe -.dr-aw-- -ingswvhereinilikenumeralsfoflreferencedesignate ,thessarnemartsi-in,eachtofthegureafthe:numeral .I li'Iiesrlgnezes ffa .container, @or vrbueket, preferably .eylindriealxin ,shape and fwhose lowereend `bastat- .havingitheleentraltpilotwhiehais .oigan inverted, conical shape. r(;)n..eppc1site sides,- of the vpilot-.the .flowenendthebucketihasiapproximately radial xslats' 4,- fandcbehindzthemsthescrapers 5,"5, (which ....20 sare forwardly ipitched eso as :torgather the loose earth fon Athe bottom ,fzof the nbore and rdirect `it fthreugh .the .slots i4 :into -the `bucket, or ccan .tainen I. y

A t ithefnpper fend toi -sthe bucket Lthere are bthe .25 .transverse ladjacent .plates 16, e6, which vextendfa selected distancesdcwn intothebucke-taand 4whose ,margins fmayrbasecuredato, thezwalls of .the-.bucket rinianyipreferred mantienes by melding.

,Qnionesidefofthesplates ,6,- 6 fthere `is -one side 230 alot-1,.iandlonrthetotherfside df the Plplatesl, :6,

there isv another side slot 1. 'These slots are vertical and are cut through the wall of the bucket of the plates 8 and jaws 9 and is fitted alsok through the slot I0 as more clearly shown in Figure 2. The assembly formed of the plates 6, 6 has the upwardly diverging grooves I2, I2 on opposite sides to receive the guide studs I3, I 3 which are'ancho'red to the corresponding plates 8, 8. There are the plate-like blades I4, I 4 which are fastened, in any preferred manner, as by welding, to the forward sides of the corresponding reinforcing plates 8, 8. The outer margins of the blades I4 are forwardly curved, as more accurately shown in Figures 4 and 5 and terminate in the scraping or reaming edges I5, I5. 'Ihe curvature of said blades at their 'lower ends is such that Y tted through the socket'member and the drivwhen the blades are in retracted position they will substantially close the slots I at their lower .ends as indicated in Figure so as to retain the cuttings in the container, or bucket, I.

The upper'ends of theA plate-like jaws 9, 9 are secured, preferably by welding, to the lowerrend of the upstanding driving socket member I 6 which is preferably square in horizontal, cross-section.

It is provided to receive the correspondingly Vshaped'lower endof a driving sternv I1 kwhich-may be retained therein bynieans of vthecross-pin I8 ing stem as shown in Figure 3.

progressively expanded. VThe forward curvature of the blades will gradually force the cuttings in- Y wardly through the side slots I and when the upper ends of the grooves I2 engagethe pins or studs I3 the blades will be fully expanded and the underreaming of the bore will be fully ac complished. The range of outward movement of the blades and the consequent enlargement of the bore may be determined by the length of the slots I0,andj grooves I2`and1the size ofthe blades.

As the blades are 'moved downward and outwardly the springs I9, i9 will be placed under-tension.

Strong coil springs I9, I9 are attached at vone I end to the upper end of the bucket and at their other ends to thebrackets 20, :arried by the lower ends of the jaws 9, 9.w

In operation the blades Willbe inretracted-po`vlv sition within the bucket I as shown' in vFigures l;

and 2 when lowered into the hole I9. When the underreamer lands on the bottom of the hole the pilot 3Vwill penetrateinto the formation and will hold the bucket-,centered during rotation.' The driving stem I 'I may then beV rotated in an appropriate direction and'by any suitable mechanism provided for the purpose. Th'e downward thrust of the driving stem will tend to move vthe plates 8 and blades I4 downwardly, the clarnpbvolt II moving downwardly in the slot I0. During this ydownwardY movement of the plates, the blades will also be graduallyexpanded that is, their lower ends will be moved radially outwardly 'dues to the pins, orv studs, I3 engagingin the vdown- Wardly diverging grooves I2, I2, inthe plate assembly A(i, I through the slots 'I and nally reaching their extreme outer position asV shown in Figure 3.

6, said blades moving outwardly Asthe blades move outwardly they will also gradually move downwardly'V so that their lower ends move, or thrust, outwardly ina horizontal direction to the endthat the lower end of the bore, when underreamed, will lie in an approximately horizontal plane as shown in Figure 3. To accomplishthis the lower ends of the blades Mare y cutjon the diagonal, as shown'in Figures 1 and'4 2, and terminate in sharpcutting edges. As the underreamer is rotated the blades will come into cutting contactV with the Vsides of the h'ole and the formation will be gradually'reamed away from the side walls at thevr bottom asfthe blades are Thereupon'the underreamer may be lifted outv of the bore by an upward pull on the driving 'stein'l'L This will operate lirst to retract the [blades inwardly but Ythe tension of said springs.

will hold the lower end of the bucket firmly Y against the bottom 'of the bore. while the blades are being withdrawn so that the loose earth will be drawn into the bucket rather than underneath it. When the clamp bolt I I reaches the upper end of Athe slot I0, the entire tool will then be moved upwardly and may be completely withdrawn from the bore. The yslots being narrow, the earth in the bucket will bridge over them and notfall out. Wl'ien the tool reaches'the ground surfacelthe driving stem may again be lowered Y thus'movingv the blades outwardly and rendering the'interior of the bucket accessible so that the contents thereof maybe discharged.

The drawings and description are illustrative merely, while the broad principle of the invention will be dened by the appended claim.V i .Y What I claim is:

An 1 underreamer comprising Va cylindrical bucket having side slots, a transverse supporting plate assembly anchored in the top of vtheV bucket and having a vertical slot extending transversely the reamers 

